According to Sakurai's Weekly Famitsu Column, the characters Jigglypuff, Toon Link and Wolf almost didn't make it into Brawl, and were added in the final stages of development, hence the reason they had no significant roles in the storyline of the Subspace Emissary.

In that case, Jigglypuff might not have as big as a chance as one would expect, seeing how Jigglypuff was almost cut from Brawl.

That's a good point. But by being in Brawl, Jiggs has become even more of a Smash staple, making her chances of getting cut in this lower than they were in Brawl.